feat: tracer supports MultiQueryTracer

[uh-zz]

It able to set tracer and logger respectively.

#1950

[jackc]

As I mentioned on my comment to #1950:

One thing I would be concerned about is how to handle multiple tracers that each implement different hooks. I'm sure it could be handled but it might be a little tricky to both have a clean interface and avoid a performance hit.

As far as I can tell this does not account for this case at all. What if one of tracers implemented pgx.BatchTracer?

[rubiagatra]

Any update @uh-zz ?

[uh-zz]

@rubiagatra
Thank you for the mention. I haven't been able to work on this issue for a while. As @jackc san commented, I haven't considered the performance hit when supporting multiple tracers, so further verification may be necessary.

Until it is supported, the following issue might be helpful:

• How to improve logging and tracing support in future release? #1061

[rubiagatra]

Maybe I can help, I will take a look the following issue